Green sheet slurry, green sheet, production method of green sheet slurry, production method of green sheet, and production method of electronic device

ABSTRACT

A green sheet slurry, characterized by including ceramic powder, a binder resin, a plasticizer and a solvent, wherein the binder resin contains a polyvinyl butyral resin, a polymerization degree of the polybutyral resin is 1000 or more and 1700 or less, a nominal value of a butyralation degree of the resin is 65% or higher and 78% or lower, and a residual acetyl group amount is smaller than 6%.

TECHNICAL FIELD

The present invention relates to a green sheet slurry, a green sheet, aproduction method of a green sheet slurry, a production method of agreen sheet, and a production method of an electronic device and,particularly relates to a slurry, green sheet and a method capable ofproducing a green sheet having excellent handlability and adhesivenesseven in the case of an extremely thin sheet and suitable to making anelectronic device a thin layer and multilayer.

BACKGOUND ART

In recent years, as a variety of electronic equipments become compact,electronic devices to be installed inside the electronic equipments havebecome smaller and higher in performance. As one of the electronicdevices, there is a ceramic electronic device, such as a CR built-insubstrate and a multilayer ceramic capacitor, and the ceramic electronicdevices have been required to be smaller and higher in performance.

To pursue a smaller ceramic electronic device having a highercapacitance, there is a strong demand for thinking a dielectric layer.Recently, a thickness of a dielectric green sheet has become about μm orless.

To produce a ceramic green sheet, normally, a ceramic slurry composed ofceramic powder, a binder (an acrylic based resin and a butyral basedresin, etc.), a plasticizer (phthalate esters, glycols, adipic acids,and phosphoric esters) and an organic solvent (toluene, MEK (MethyleEthyle keton) and acetone, etc.) are prepared. Next, the ceramic slurrycoated on a carrier film (a carrier film made by PET and PP) by usingthe doctor blade method, etc. and dried by heating.

Also, a method of producing by preparing a ceramic slurry wherein theceramic powder and binder are mixed in a solvent, then, 2-Dimensionaldrawing a film-shaped item obtained by extruding slurry has beenconsidered in recent years.

A method of producing a multilayer ceramic capacitor by using theceramic green sheet explained above will be explained in detail. Aninternal electrode conductive paste containing metal powder and a binderis printed to be a predetermined pattern on the ceramic green sheet anddried to form an internal electrode pattern. After that, the green sheetis peeled from the carrier film and stacked by a predetermined number oflayers. Here, two methods are proposed, that are a method of peeling thegreen sheet from the carrier film before stacking in layers and a methodof peeling the carrier film after stacking in layers and adhering bycompression, but the difference is not large. Finally, the stacked bodyis cut to be chips, so that green chips are prepared. After firing thegreen chips, external electrodes are formed, so that a multilayerceramic capacitor and other electronic devices are produced.

When producing a multilayer ceramic capacitor, an interlayer thicknessof sheets formed with internal electrodes is in a range of 3 μm to 100μm or so based on a desired capacitance required as a capacitor. Also,in a multilayer ceramic capacitor, a part not formed with internalelectrodes is formed on an outer part in the stacking direction of thecapacitor chip.

In such a multilayer ceramic capacitor, it was general to use apolyvinyl butyral resin having a polymerization degree of 1000 or less(Mw=50,000) as a binder to be used (refer to the patent article 1 below:the Japanese Patent Publication No. 10-67567). As the reasons, tosufficiently secure adhesiveness of ceramic green sheets at the time ofstacking, to reduce surface roughness of the green sheets, to secureplasticity of the green sheets, and to reduce viscosity of slurry may bementioned. As a plasticizer, generally, phthalic acid, adipic acid,sebacic acid, and phosphoric esters can be used, which were selected interms of a boiling point and hazardous property, etc. in an object ofgiving plasticity.

In recent years, as electronic equipments become more compact,electronic devices to be used therein have rapidly become more compact.In multilayer electronic devices as typified by a multilayer ceramiccapacitor, rapid development has been made on increasing the number oflayers to be stacked and attaining a thinner interlayer thickness. Torespond to the technical trends, a thickness of a green sheet, whichdetermines the interlayer thickness, has almost become 3 μm or less to 2μm or less. Therefore, in a production process of a multilayer ceramiccapacitor, it is necessary to handle extremely thin green sheets and todesign very advanced green sheet properties.

As characteristics required as the properties of such an extremely thingreen sheet, sheet strength, flexibility, smoothness, adhesiveness whenbeing stacked, handlability (electrostatic property), etc. may bementioned, and balance of a higher order is required.

Note that, as shown in the patent article 2: the Japanese UnexaminedPatent Publication No. 6-206756, there is known a technique of using apolyvinyl butyral resin having a polymerization degree of 1000 or moreas a binder in green sheet slurry containing an aqueous solvent for apurpose of eliminating a short-circuiting defect.

However, the patent article 2 is not for particularly attaining athinner organic solvent based green sheet, and a range of apolymerization degree of a polyvinyl butyral resin is not limited to aspecified range. Moreover, a butyralation degree and a residual acetylgroup amount of the resin are not focused at all.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a green sheet slurry, agreen sheet, a production method of a green sheet slurry and aproduction method of a green sheet capable of producing a green sheethaving enough strength to be peeled from a carrier film, preferableadhesiveness and handlability even if the green sheet is extremely thin.Also, another object of the present invention is to provide a productionmethod of an electronic device suitable to be made thinner andmultilayer.

The present inventors have been committed themselves to study to attainthe above objects, found that it was possible to produce a green sheethaving enough strength to be peeled from a supporting body, preferableadhesiveness and handlability even if the green sheet was extremelythin, by using as a binder a polyvinyl acetal resin having apolymerization degree in a specific range and a residual acetyl groupamount of a predetermined value or smaller, and completed the presentinvention.

Namely, a green sheet slurry according to a first aspect of the presentinvention is characterized by including ceramic powder, a binder resin,a plasticizer and a solvent, wherein

the binder resin contains a polyvinyl butyral resin, a polymerizationdegree of the polybutyral resin is 1000 or more and 1700 or less, anominal value of a butyralation degree of the resin is 65% or higher and78% or lower, and a residual acetyl group amount is smaller than 6%. Thesolvent is not particularly limited and an organic solvent is preferablyused. Note that a nominal value of the butyralation degree varies in arange of ±3%. Namely, a nominal value of a butyralation degree of 65%means 65±3%. In the following explanation, when referring simply by “abutyralation degree”, it means “a nominal value of a butyralationdegree”.

In the first aspect of the present invention, when the polymerizationdegree of the polybutyral resin is too low, it is liable that sufficientmechanical strength is hard to be obtained in the case of making thelayer thinner, for example, to 5 μm or less, preferably 3 μm or less.While when the polymerization degree is too high, it is liable thatsurface roughness is increased when made to be a sheet. Also, when abutyralation degree of the polybutyral resin is too low, solubility in aslurry tends to become poor, while when too high, surface roughness ofthe sheet tends to decline. Furthermore, when a residual acetyl groupamount is too large, surface roughness of the sheet tends to decline.

According to the green sheet slurry according to the first aspect of thepresent invention, it is possible to produce a green sheet having enoughstrength to be peeled from a supporting body, preferable adhesivenessand handlability even if the green sheet is extremely thin.

A green sheet slurry according to a second aspect of the presentinvention includes ceramic powder, a binder resin, a plasticizer and anorganic solvent, wherein

water is contained by 1 part by weight or more and 6 parts by weight orless with respect to 100 parts by weight of the ceramic powder.

Conventionally, a green sheet slurry using an organic solvent had to beproperly managed in order not to be mixed with water to prevent thecharacteristics from changing due to absorbing moisture. In the secondaspect of the present invention, water is positively mixed by a contentin a predetermined range from the beginning of producing the slurry.Therefore, in the present invention, it is not necessary to strictlymanage water absorbance due to moisture.

When the water content is too low, characteristics of the slurry widelychange over time due to moisture absorbance, which is preferable, theviscosity tends to increase in the slurry, and filtration propertiestend to deteriorate in the slurry. While, when the water content is toohigh, separation and precipitation of the slurry are caused, thedispersibility becomes poor and surface roughness of the sheet tends todecline.

A green sheet slurry according to a third aspect of the presentinvention is characterized by including ceramic powder, a binder resin,a plasticizer, a solvent, and a dispersant, wherein:

the dispersant contains polyethylene glycol based nonionic dispersant,and a hydrophile-lipophile balance vale is 5 to 6; and

the dispersant is added by 0.5 part by weight or more and 1.5 parts byweight or less with respect to 100 parts by weight of ceramic powder.

In the case where the dispersant is not a polyethylene glycol basednonionic dispersant, it is liable that the viscosity increases in theslurry, sheet density declines, sheet surface roughness increases, andsheet stretching property declines. Also, when the HLB of the dispersantis out of the above range, it is liable that the sheet density declinesand sheet surface roughness increases.

According to the green sheet slurry according to the third aspect of thepresent invention, it is possible to produce a green sheet having enoughstrength to be peeled from a supporting body, preferable adhesivenessand handlability even if the green sheet is extremely thin.

Also, in the third aspect of the present invention, when an addingquantity of the dispersant is too small, it is liable that viscosityincreases in the slurry, sheet density declines and sheet surfaceroughness increases. Also, when the adding quantity is too large, it isliable that tensile strength of the sheet declines and adhesiveness alsodeclines.

A green sheet slurry according to a fourth aspect of the presentinvention is characterized by including ceramic powder, a binder resin,a plasticizer, a solvent, and an antistatic agent, wherein

the antistatic agent contains an imidazoline based antistatic agent, andthe antistatic agent is contained by 0.1 part by weight or more and 0.75part by weight or less with respect to 100 parts by weight of theceramic powder.

In the fourth aspect of the present invention, when the antistatic agentis not an imidazoline based antistatic agent, the antistatic effect issmall and sheet strength, sheet ductility or adhesiveness tends todecline. According to the green sheet slurry according to the fourthaspect of the present invention, it is possible to produce a green sheethaving enough strength to be peeled from a supporting body, capable ofsuppressing static electricity electrostatic generated at the time ofbeing peeled from the supporting body, etc., and having preferableadhesiveness and handlability even if the green sheet is extremely thin.

In the fourth aspect of the present invention, when the adding quantityof the antistatic agent is too small, the antistatic effect tends toreduce, while when too large, it is liable that the sheet surfaceroughness increase and sheet strength decrease poor.

A green sheet slurry according to a fifth aspect of the presentinvention includes ceramic powder, a binder resin, and a solvent, andmay include plasticizer and dispersant if necessary, wherein

the solvent contains an alcohol based solvent and an aromatic solvent,and the aromatic solvent is contained by 10 parts by weight or more and20 parts by weight or less when assuming that total weight of thealcohol based solvent and aromatic solvent is 100 parts by weight. Whena content of the aromatic solvent is too small, the sheet surfaceroughness tends to increase, while when too large, the slurry filtrationproperties decline and sheet surface roughness also declines byincreasing.

Preferably, the binder resin is contained by 5 parts by weight or moreand 6.5 parts by weight or less with respect to 100 parts by weight ofthe ceramic powder. When a content of the binder resin is too small, itis liable that the sheet strength declines- and stackability(adhesiveness at the time of stacking in layers) declines. Also, when acontent of the binder resin is too large, it is liable that segregationof the binder resin is caused to deteriorate the dispersibility andsheet surface roughness declines.

Preferably, diotycle phthalate is contained as the plasticizer by 40parts by weight or more and 70 parts by weight or less with respect to100 parts by weight of the binder resin. Comparing with otherplasticizers, dioctyl phthalate is preferable in terms of both of sheetstrength and sheet ductility, and particularly preferable because therelease strength from a supporting body is small and it is easilypeeled. Note that when a content of the plasticizer is too small, it isliable that sheet stretching becomes less and flexibility becomes less.Also, when the content is too large, it is liable that breedout of theplasticizer from the sheet is caused, segregation of the plasticizer iseasily caused against the sheet, and the sheet dispersibility declines.

Preferably, when assuming that total volume of the ceramic powder,binder resin and plasticizer is 100 volume %, a volume ratio accountedby the ceramic powder is 64.3% or higher and 72% or lower. When thevolume ratio is too small, it is liable that segregation of a binder iseasily caused to deteriorate the dispersibility, and the surfaceroughness declines. While when the volume ratio is too large, it isliable that the sheet strength declines and stackability also declines.

Preferably, at least one of a hydrocarbon based solvent, industrialgasoline, kerosene and solvent naphtha is added by 3 parts by weight ormore and 15 parts by weight or less with respect to 100 parts by weightof the ceramic powder. By adding these additives, the sheet strength andsheet surface roughness can be improved. When an adding quantity ofthese additives is too small, effects of adding is small, while when theadding quantity is too large, it is liable that the sheet strength andsheet surface roughness decline inversely.

A production method of a green sheet slurry according to the presentinvention is characterized in that

the binder resin is dissolved in an alcohol based solvent of at leastone kind of methanol, ethanol, propanol and butanol and filtered to makea solution in advance, and the ceramic powder and other components areadded to the solution.

A binder resin having a high polymerization degree is hard to bedissolved in a solvent, and dispersibility of a slurry tends to declinein a normal method in a method of the present invention, a binder resinhaving a high polymerization degree is dissolved in a good solvent asexplained above, and ceramic powder and other components are added tothe solution, so that dispersibility of a slurry can be improved andgeneration of undissolved resin can be suppressed. Note that solidcontent concentration cannot be raised and changes of lacquer viscositytend to become large over time in the case of a solvent other than theabove solvents.

A production method of a ceramic green sheet according to the presentinvention includes:

a step of preparing the above green sheet slurry; and

a step of forming a ceramic green sheet by using the green sheet slurry.

A production method of a ceramic electronic device according to thepresent invention includes:

a step of preparing the above green sheet slurry;

a step of forming a ceramic green sheet by using the green sheet slurry;

a step of drying the green sheet;

a step of stacking dried green sheets via internal electrode layers toobtain a green chip; and

a step of firing the green chip.

The green sheet according to the present invention is produced by usingthe above green sheet slurry.

BRIEF DESCRIPTION OF DRAWINGS

Below, the present invention will be explained based on embodimentsshown in drawings.

FIG. 1 is a schematic sectional view of a multilayer ceramic capacitoraccording to an embodiment of the present invention;

FIG. 2A to FIG. 2C are sectional views of a key part showing a transfermethod of an electrode layer;

FIG. 3A to FIG. 3C are sectional views of a key part showing stepscontinued from FIG. 2;

FIG. 4A to FIG. 4C are sectional views of a key part showing a method ofstacking a green sheet adhered with an electrode layer;

FIG. 5A to FIG. 5C are sectional views of a key part showing a method ofstacking a green sheet adhered with an electrode layer, showing stepscontinued from FIG. 4;

FIG. 6A to FIG. 6C are sectional views of a key part showing stepscontinued from FIG. 5;

FIG. 7 is a sectional view of a key part showing a step continued fromFIG. 6; and

FIG. 8 is a sectional view of a key part showing a step continued fromFIG. 7.

BEST MODE FOR CARRYING OUT THE INVENTION

First, as an embodiment of an electronic device produced by using agreen sheet slurry (dielectric paste) and a green sheet according to thepresent invention, an overall configuration of a multilayer ceramiccapacitor will be explained.

As shown in FIG. 1, a multilayer ceramic capacitor 2 according to thepresent embodiment comprises a capacitor element 4, a first terminalelectrode 6 and a second terminal electrode 8. The capacitor element 4comprises dielectric layers 10 and internal electrode layers 12, and theinternal electrode layers 12 are stacked alternately between thedielectric layers 10. The alternately stacked internal electrode layers12 on one side are electrically connected to inside of the firstterminal electrode 6 formed outside of one end portion of the capacitorelement 4. Also, the alternately stacked internal electrode layers 12 onthe other side are electrically connected to inside of the secondterminal electrode 8 formed outside of the other end portion of thecapacitor element 4.

In the present embodiment, an internal electrode layer 12 is formed bytransferring an electrode layer 12 a to a ceramic green sheet 10 a asshown in FIG. 2 to FIG. 6 as will be explained later on.

A material of the dielectric layer 10 is not particularly limited andcomposed of a dielectric material, for example, calcium titanate,strontium titanate and/or barium titanate, etc. A thickness of each ofthe dielectric layers 10 is not particularly limited, but those having athickness of several μm to several hundreds of μm are general.Particularly in the present embodiment, it is made to be thin aspreferably 5 μm or less, and more preferably 3 μm or less.

A material of the terminal electrodes 6 and 8 is not particularlylimited, however, copper, a copper alloy, nickel and a nickel alloy,etc. are normally used. An alloy of silver and silver with palladium maybe also used. A thickness of the terminal electrodes 6 and 8 is notparticularly limited, however, but is normally 10 to 50 μm or so.

A shape and size of the multilayer ceramic capacitor 2 may be suitablydetermined in accordance with the object and use. When the multilayerceramic capacitor 2 has a rectangular parallelepiped shape, it isnormally a length (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm)×width (0.3to 5.0 mm, preferably 0.3 to 1.6 mm)×thickness (0.1 to 1.9 mm,preferably 0.3 to 1.6 mm) or so.

Next, an example of production methods of the multilayer ceramiccapacitor 2 according to the present embodiment will be explained.

(1) First, a dielectric slurry (green sheet slurry) is prepared toproduce a ceramic green sheet for composing the dielectric layers 10shown in FIG. 1 after firing.

The dielectric slurry is composed of an organic solvent based slurryobtained by dispersing a dielectric material (ceramic powder) and anorganic vehicle.

The dielectric material is suitably selected from a variety of compoundswhich become composite oxides or oxides, such as carbonates, nitrites,hydroxides, and organic metal compounds, and mixed for use. Thedielectric material is normally used as powder having an averageparticle diameter of 0.4 μm or less, and preferably 0.1 to 3.0 μm orless or so. Note that it is preferable to use finer powder than thegreen sheet thickness to form an extremely thin green sheet.

The organic vehicle is obtained by dissolving a binder resin in anorganic solvent. As the binder resin used for the organic vehicle, apolyvinyl butyral resin is used in the present embodiment. Apolymerization degree of the polybutyral resin is 1000 or higher and1700 or lower, and preferably 1400 to 1700. Also, a butyralation degreeof the resin is 65% or higher and 78% or lower, and preferably 65% orhigher and 70% or lower, and the residual acetyl group amount is lessthan 6% and preferably 3% or less.

The polymerization degree of the polybutyral resin can be measured, forexample, by a polymerization degree of a polyvinyl acetal resin as amaterial. Also, the butyralation degree can be measured, for example,based on the JISK6728. Furthermore, the residual acetyl group amount canbe measured based on the JISK6728.

When the polymerization degree of the polybutyral resin is too low, itis liable that sufficient mechanical strength is hard to be obtainedwhen made to be a thin film of, for example, 5 μm or less, andpreferably 3 μm or less or so. Also, when the polymerization degree istoo large, surface roughness tends to decline when made to be a sheet.Also, when the butyralation degree of the polybutyral resin is too low,solubility in a slurry tends to decline, while when too high, sheetsurface roughness tends to decline. Furthermore, when the residualacetyl group amount is too large, sheet surface roughness tends todecline.

An organic solvent to be used for an organic vehicle is not particularlylimited and an organic solvent, such as terpionel, alcohol, butylcarbitol, acetone and toluene, is used. In the present embodiment, theorganic solvent preferably contains an alcohol based solvent and anaromatic solvent, and the aromatic solvent is contained by 10 parts byweight or more and 20 parts by weight or less when assuming total weightof the alcohol based solvent and aromatic solvent is 100 parts byweight. When a content of the aromatic solvent is too small, sheetsurface roughness tends to increase, while when too large, the slurryfiltration properties decline and sheet surface roughness also declinesby increasing.

As an alcohol based solvent, methanol, ethanol, propanol and butanol,etc. may be mentioned. As an aromatic solvent, toluene, xylene andbenzyl acetate, etc. may be mentioned.

It is preferable that a binder resin is dissolved in an alcohol basedsolvent of at least one kind of methanol, ethanol, propanol and butanoland filtered to be a solution in advance, and dielectric powder andother components are added to the solution. A binder resin having a highpolymerization degree is hard to be dissolved in a solvent, anddispersibility of a slurry tends to decline in a normal method. In amethod of the present embodiment, a binder resin having a highpolymerization degree is dissolved in the above good solvent and ceramicpowder and other components are added to the solution, so thatdispersibility of a slurry can be improved and generation of undissolvedresin can be suppressed. Note that solid content concentration cannot beraised and changes of lacquer viscosity tend to become large over timein the case of a solvent other than the above solvents.

In the dielectric slurry, additives selected from a variety ofdispersants, plasticizers, antistatic agents, dielectrics, glass flit,and insulators may be included in accordance with need.

In the present embodiment, a dispersant is not particularly limited, butpolyethylene glycol based nonionic dispersant is preferably used, and ahydrophile-lipophile balance (HLB) value thereof is 5 to 6. A dispersantis added by 0.5 part by weight or more and 1.5 parts by weight or less,and more-preferably 0.5 part by weight or more and 1.0 part by weight orless with respect to 100 parts by weight of ceramic powder.

When the HLB is out of the above ranges, it is liable that slurryviscosity increases and sheet surface roughness increases. Also, in thecase of a dispersant other than a polyethylene glycol based nonionicdispersant, slurry viscosity increases, sheet surface roughnessincreases and sheet flexibility dec lines, so that it is not preferable.

When an adding quantity of a dispersant is too small, sheet surfaceroughness tends to increase, while when too large, sheet tensilestrength and stackability tend to decline.

In the present embodiment, dioctyl phthalate is preferably used as aplasticizer and contained by an amount of preferably 40 parts by weightor more and 70 parts by weight or less, and more preferably 40 to 60parts by weight with respect to 100 parts by weight of a binder resin.Comparing with other plasticizers, dioctyl phthalate is preferable interms of both of sheet strength and sheet stretch and is particularlypreferable for having weak peeling strength so as to be easily peeledfrom a supporting body. Note that when a content of the plasticizer istoo small, it is liable that sheet stretch becomes less andflexibility-becomes less. Also, when the content is too large, it isliable that breedout of a plasticizer from a sheet is caused,segregation of the plasticizer against the sheet easily arises anddispersibility of the sheet declines.

Also, in the present embodiment, the dielectric slurry contains water by1 part by weight or more and 6 parts by weight or less, and preferably 1to 3 parts by weight with respect to 100 parts by weight of dielectricpowder. When a water content is too small, changes of slurrycharacteristics due to moisture absorbance over time becomes large,which is preferable, slurry viscosity tends to increase and filtrationproperties of the slurry tend to decline. While when the water contentis too large, separation and precipitation of the slurry are caused, thedispersibility becomes poor and surface roughness of the sheet tends todecline.

Furthermore, in the present embodiment, at least any one of ahydrocarbon based solvent, industrial gasoline, kerosene, and solventnaphtha is added by preferably 3 parts by weight or more and 15 parts byweight or less, and more preferably 5 to 10 parts by weight with respectto 100 parts by weight of dielectric powder. By adding these additives,sheet strength and sheet surface roughness can be improved. When anadding quantity of these additives is too small, effects of adding issmall, while when the adding quantity is too large, it is liable thatsheet strength and sheet surface roughness are deteriorated inversely.

A binder resin is contained preferably by 5 parts by weight or more and6.5 parts by weight or less with respect to 100 parts by weight ofdielectric powder. When a content of the binder resin is too small, itis liable that the sheet strength declines and stackability(adhesiveness at the time of stacking in layers) also declines. Whilewhen a content of the binder resin is too large, it is liable thatsegregation of the binder resin is caused to make the dispersibilityworse and sheet surface roughness tends to decline.

When assuming that total volume of the ceramic powder, binder resin andplasticizer is 100 volume %, a volume ratio accounted by the dielectricpowder is preferably 62.42% or more and 72.69% or less, and morepreferably 63.93% or more and 72.69% or less. When the volume ratio istoo small, it is liable that segregation of the binder is easily causedto make the dispersibility worse and surface roughness declines. Also,when the volume ratio is too large, it is liable that the sheet strengthdeclines and the stackability also declines.

Particularly, in the present embodiment, the dielectric slurrypreferably includes an antistatic agent, and the antistatic agent ispreferably imidazoline based antistatic agent. When the antistatic agentis not an imidazoline based antistatic agent, the antistatic effect issmall and the sheet strength, sheet ductility or adhesiveness tends todecline.

An antistatic agent is contained by 0.1 part by weight or more and 0.75part by weight or less, and more preferably 0.25 to 0.5 part by weightwith respect to 100 parts by weight of ceramic powder. When an addingquantity of the antistatic agent is too small, the antistatic effectbecomes small, while when too large, it is liable that surface roughnessof the sheet declines and sheet strength declines. When the antistaticeffect is too small, static electricity easily arises when peeling thecarrier film 30 as a supporting body from the ceramic green sheet 10 a,and a disadvantage that the green sheet gets wrinkled, etc. easilyarises.

By using the dielectric slurry, for example as shown in FIG. 3A, a greensheet 10 a is formed to be a thickness of preferably 0.5 to 30 μm, andmore preferably 0.5 to 10 μm or so on the carrier film 30 as a secondsupporting sheet by the doctor blade method, etc. The green sheet 10 ais dried after being formed on the carrier film 30. Temperature ofdrying the green sheet 10 a is preferably 50 to 100° C. and drying timeis preferably 1 to 20 minutes. A thickness of the green sheet 10 a afterdrying is contracted to 5 to 25% of that before drying. The thickness ofthe green sheet after drying is preferably 3 μm or less.

(2) As shown in FIG. 2A, a carrier film 20 as a first supporting sheetis prepared separately from the carrier film 30, and a release layer 22is formed thereon. Furthermore, on top thereof, an electrode layer 12 ahaving a predetermined pattern is formed. Before or after that, on asurface of the release layer 22 where the electrode layer 12 a is notformed, a blank pattern layer 24 having substantially the same thicknessas that of the electrode layer 12 a is formed.

As the carrier films 20 and 30, for example, a PET film, etc. is used,and those coated with silicone resin, etc. are preferable to improve therelease property. Thicknesses of the carrier films 20 and 30 are notparticularly limited and are preferably 5 to 100 μm. The thicknesses ofthe carrier films 20 and 30 may be same or different.

The release layer 22 preferably contains the same dielectric powder asthe dielectric composing the green sheet 10 a shown in FIG. 3A. Also,the release layer 22 contains a binder, a plasticizer and a releaseagent other than the dielectric powder. A particle diameter of thedielectric powder may be the same as that of the dielectric particlesincluded in the green sheet but it is preferable to be smaller.

In the present embodiment, a thickness t2 of the release layer 22 ispreferably not more than a thickness of the electrode layer 12 a, andmore preferably, it is set to be a thickness of 60% or less, and furtherpreferably 30% or less.

A method of applying the release layer 22 is not particularly limited,but it has to be formed to be extremely thin, so that an applying methodusing, for example, a wire bar coater or a die coater is preferable.Note that adjustment of the release layer thickness can be made byselecting a wire bar coater having a different wire diameter. Namely, tomake the thickness of the release layer to be applied thinner, it can bedone by selecting one having a small wire diameter, inversely, to formit thick, one with a large wire diameter may be selected. The releaselayer 22 is dried after being applied. The drying temperature ispreferably 50 to 100° C. and the drying time is preferably 1 to 10minutes.

A binder for the release layer 22 is composed, for example, of anacrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol,polyolefin, polyurethane, polystyrene, or an organic composed of acopolymer of these or emulsion. The binder contained in the releaselayer 22 may be the same as the binder contained in the green sheet 10 aor may be different from that, but preferably the same.

A plasticizer for the release layer 22 is not particularly limited and,for example, phthalate ester, dioctyl phthalate, adipic acid, phosphateester and glycols, etc. may be mentioned. The plasticizer to becontained in the release layer 22 may be the same as that contained inthe green sheet 10 a or may be different from that.

A release agent for the release-layer 22 is not particularly limitedand, for example, paraffin, wax and silicone oil, etc. may be mentioned.A release agent contained in the release layer 22 may be the same asthat contained in the green sheet 10 a or may be different from that.

A binder is contained in the release layer 22 by preferably 2.5 to 200parts by weight, more preferably 5 to 30 parts by weight, andparticularly preferably 8 to 30 parts by weight or so with respect to100 parts by weight of dielectric particle.

A plasticizer is preferably contained in the release layer 22 by 0 to200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder.

A release agent is preferably contained in the release layer 22 by 0 to100 parts by weight, preferably 2 to 50 parts by weight, and morepreferably 5 to 20 parts by weight with respect to 100 parts by weightof the binder.

After forming the release layer 22 on the surface of the carrier film30, as shown in FIG. 2A, an electrode layer 12 a to compose an internalelectrode layer 12 after firing is formed to be a predetermined patternon the surface of the release layer 22. A thickness of the electrodelayer 12 a is preferably 0.1 to 2 μm, and more preferably 0.1 to 1.0 μmor so. The electrode layer 12 a may be configured by a single layer ortwo or more layers having different compositions.

The electrode layer 12 a can be formed on the surface of the releaselayer 22 by a thick film formation method, such as a printing methodusing an electrode slurry, or a thin film method, such as evaporationand sputtering. When forming the electrode layer 12 a on the surface ofthe release layer 22 by a screen printing method or a gravure printingmethod as a kind of thick film method, it is as follows.

First, an electrode slurry is prepared. The electrode slurry isfabricated by kneading a conductive material composed of a variety ofconductive metals and alloys, or a variety of oxides, organic metalcompounds or resinates, etc. to be conductive materials after firingwith an organic vehicle.

As a conductive material to be used when producing the electrode slurry,Ni, a Ni alloy and a mixture of these are used. A shape of theconductive materials is not particularly limited and may be a sphericalshape and scale-like shape, etc. or a mixture of these shapes. Thosehaving an average particle diameter of the conductive powder of normally0.1 to 2 μm, and preferably 0.2 to 1 μm or so may be used.

An organic vehicle contains a binder and a solvent. As the binder, forexample, ethyl cellulose, an acrylic resin, polyvinyl butyral, polyvinylacetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or acopolymer of these may be mentioned. Particularly, butyrals, such aspolyvinyl butyral, are preferable.

The binder is contained in the electrode paste by preferably 8 to 20parts by weight with respect to 100 parts by weight of the conductivematerial (metal powder). As a solvent, any of well-known ones, such asterpionel, butylcarbitol and kerosene, may be used. A content of thesolvent is preferably 20 to 55 wt % or so with respect to the entireslurry.

To improve the adhesiveness, the electrode slurry preferably contains aplasticizer. As a plasticizer, benzylbutyl phthalate (BBP) and otherphthalate esters, adipic acids, phosphoric esters, and glycols, etc. maybe mentioned. The plasticizer in the electrode slurry is preferably 10to 300 parts by weight, and more preferably 10 to 200 parts by weightwith respect to 100 parts by weight of the binder. Note that when anadding quantity of the plasticizer or adhesive is too large, it isliable that strength of the electrode layer 12 a remarkably declines.Also, to improve transferability of the electrode layer 12 a, it ispreferable to improve adhesiveness and/or adherence of the electrodeslurry by adding a plasticizer and/or adhesive in the electrode slurry.

After or before forming the electrode layer in a predetermined patternon the surface of the release layer 22 by a printing method, a blankpattern layer 24 is formed to be substantially the same thickness asthat of the electrode layer 12 a on the surface of the release layer 22not formed with the electrode layer 12 a. The blank pattern layer 24 iscomposed of the same material as that of the green sheet 10 a shown inFIG. 3A and formed by the same method. The electrode layer 12 a and theblank pattern layer 24 are dried in accordance with need. The dryingtemperature is not particularly limited, but is preferably 70 to 120°C., and the drying time is preferably 5 to 15 minutes.

(3) As shown in FIG. 2A, an adhesive layer transfer sheet formed with anadhesive layer 28 is prepared on the surface of a carrier film 26 as athird supporting sheet separately from the carrier films 20 and 30explained above. The carrier film 26 is formed by the same sheet as thatof the carrier films 20 and 30.

A composition of the adhesive layer 28 is the same as that of therelease layer 22 except for not containing a release agent. Namely, theadhesive layer 28 contains a binder, a plasticizer and a release agent.The adhesive layer 28 may contain the same dielectric particle as thatof the dielectrics composing the green sheet 10 a, however, in the caseof forming an adhesive layer having a thinner thickness than a particlediameter of the dielectric particles, it is better not to containdielectric particles. Also, when dielectric particles are contained inthe adhesive layer 28, a particle diameter of the dielectric particlesis preferably smaller than the particle diameter of the dielectricparticles contained in the green sheet.

A plasticizer is preferably contained in the adhesive layer 28 by 0 to200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder.

The adhesive layer 28 further contains an antistatic agent, and theantistatic agent includes one of imidazoline based surfactants, andweight based adding quantity of the antistatic agent is preferably notmore than that of the binder (organic polymer material). Namely, theantistatic agent is preferably contained in the adhesive layer 28 by 0to 200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder.

A thickness of the adhesive layer 28 is preferably 0.02 to 0.3 μm or so,more preferably, thinner than an average particle diameter of dielectricparticles contained in the green sheet. Also, a thickness of theadhesive layer 28 is preferably 1/10 or less of a thickness of the greensheet 10 a.

When a thickness of the adhesive layer 28 is too thin, the adhesiveforce declines, while when too thick, a space is easily formed inside anelement body after sintering depending on the thickness of the adhesivelayer, and a capacitance by an amount of the volume tends to decreaseremarkably.

The adhesive layer 28 is formed on the surface of the carrier film 26,for example, by a bar coater method, die coater method, reverse rollcoater method, dip coater method and kiss coater method, etc. and driedin accordance with need. The drying temperature is not particularlylimited, but is preferably the room temperature to 80° C., and thedrying time is preferably 1 to 5 minutes.

(4) To form the adhesive layer on the surface of the electrode layer 12a and the blank pattern layer 24 shown in FIG. 2A, a transfer method isapplied in the present embodiment. Namely, as shown in FIG. 2B, theadhesive layer 28 of the carrier film 26 is pressed against the surfaceof the electrode layer 12 a and the blank pattern layer 24, heated andpressed, then, the carrier film 26 is removed. Consequently, as shown inFIG. 2C, the adhesive layer 28 is transferred to the surface of theelectrode layer 12 a and the blank pattern layer 24. Note that transferof the adhesive layer 28 may be performed on the surface of the greensheet 10 a shown in FIG. 3A.

The heating temperature at transferring is preferably 40 to 100° C., andthe pressing force is preferably 0.2 to 15 MPa. Pressing may beperformed by a press or a calendar roll, but is preferably performed bya pair of rolls.

After that, the electrode layer 12 a is adhered to the surface of thegreen sheet 10 a formed on the surface of the carrier film (carrierfilm) 30 shown in FIG. 3A. For that purpose, as shown in FIG. 3B, theelectrode layer 12 a and the blank pattern layer 24 of the carrier film20 are pressed via the adhesive layer 28 against the surface of thegreen sheet 10 a together with the carrier film 20, heated and pressed.As a result, as shown in FIG. 3C, the electrode layer 12 a and the blankpattern layer 24 are transferred to the surface of the green sheet 10 a.Note that since the carrier film 30 on the green sheet side is peeledoff, when seeing from the green sheet 10 a side, the green sheet 10 a istransferred to the electrode layer 12 a and the blank pattern layer 24via the adhesive layer 28.

Heating and pressing at the time of transferring may be pressing andheating by a press or by a calendar roll, but is preferably performed bya pair of rolls. The heating temperature and the pressing force are sameas those at the time of transferring the adhesive layer 28.

A single-layer electrode layer 12 a in a predetermined pattern is formedon the single green sheet 10 a by steps shown in FIG. 2A to FIG. 3C. Agreen sheet 10 a formed with the electrode layer 12 a is stacked byrepeating the steps shown in FIG. 4A to FIG. 6C. Note that the samereference numbers are given to common members with those shown in FIG.3A to FIG. 4C, and an explanation thereon is partially omitted.

First, as shown in FIG. 4A to FIG. 4C, the adhesive layer 28 istransferred to the surface on the other side of the electrode layer(back side) on the green sheet 10 a. After that, as shown in FIG. 5A toFIG. 5C, the electrode layer 12 a and the blank pattern layer 24 aretransferred to the back side of the green sheet 10 a via the adhesivelayer 28.

Next, as shown in FIG. 6A to FIG. 6C, on the surface of the electrodelayer 12 a and the blank pattern layer 24, the green sheet 10 a istransferred via the adhesive layer 28. After that, by repeating thetransfer, a multilayer block, wherein a large number of electrode layers12 a and the green sheet 10 a are alternately stacked as shown in FIG.7, is obtained.

Note that a method below may be used without applying the steps shown inFIG. 5C to FIG. 6C. Namely, from the step shown in FIG. 5B, not toremove the carrier film 20 on the lower side but to remove the carrierfilm on the upper side, and a multilayer unit U1 shown in FIG. 4C may bestacked thereon. After that, by repeating an operation of removing thecarrier film 20 on the upper side again, stacking thereon the multilayerunit U1 shown in FIG. 4C, and removing the carrier film 20 on the upperside, a multilayer block wherein a large number of electrode layers 12 aand the green sheet 10 a are alternately stacked as shown in FIG. 7 isobtained. A method of stacking the multilayer unit U1 shown in FIG. 4Cis superior in terms of an efficiency of the stacking operation.

When the number of stacking layers of the green sheet is small, a firingstep in the next step is performed by the multilayer block alone. Also,in accordance with need, a plurality of multilayer blocks as such may bestacked via adhesive layers 28 formed by a transfer method in the sameway as above to obtain a multilayer body having larger number of layers.

(5) After that, as shown in FIG. 8, a green sheet 40 for an outer layer(a thick multilayer body obtained by stacking a plurality of greensheets not formed with an electrode layer) is stacked on the lowersurface of the stacked body and the entire stacked body is supported byan absorption holder 50. After that, the carrier film 20 on the upperside is peeled off, the green sheet 40 for an outer layer is formed ontop of the multilayer body in the same way, and final pressing isperformed.

Pressure at the time of the final pressing is preferably 10 to 200 MPa.Also, the heating temperature is preferably 40 to 100° C. After that,the multilayer body is cut to be a predetermined size to form greenchips. The green chips are subjected to binder removal processing andfiring processing, then, thermal treatment is performed in order tore-oxidize the dielectric layer.

The binder removal processing may be performed under a normal condition,but when using a base metal, such as Ni and a Ni alloy, as a conductivematerial of the internal electrode layer, it is preferably performedunder the specific condition below.

temperature rising rate: 5 to 300° C./hour, particularly 10 to 50°C./hour

holding temperature: 200 to 400° C., particularly 250 to 350° C.

holding time: 0.5 to 20 hours, particularly 1 to 10 hours

atmosphere: a mixed gas of wet N₂ and H₂

A firing condition is preferably as below.

temperature rising rate: 50 to 500° C./hour, particularly 200 to 300°C./hour

holding temperature: 0.1100 to 1300° C., particularly 1150 to 1250° C.

holding time: 0.5 to 8 hours, particularly 1 to 3 hours

cooling rate: 50 to 500° C./hour, particularly 200 to 300° C./hour

atmosphere gas: a mixed gas of wet N₂ and H₂, etc.

Note that oxygen partial pressure in an atmosphere in the air at firingis preferably 10⁻² Pa or less, particularly 10⁻² to 10⁻⁸ Pa. Whenexceeding the above ranges, the internal electrode layer tends tooxidize, while when the oxygen partial pressure is too low, abnormalsintering is caused in an electrode material of the internal electrodelayer to be broken.

The thermal treatment after performing such firing is preferablyperformed with a holding temperature or highest temperature of 1000° C.or higher, more preferably 1000 to 1100° C. When the holding temperatureor the highest temperature at the time of the thermal treatment is lowerthan the above ranges, it is liable that oxidization of the dielectricmaterial is insufficient to make the insulation resistance lifetimeshort, while when exceeding the above ranges, Ni in the internalelectrode oxidizes and the capacity decreases, moreover, Ni reacts witha dielectric base and the lifetime also tends to become short. Theoxygen partial pressure at the time of thermal treatment is higher thana higher oxygen partial pressure than a reducing atmosphere at the timeof firing, preferably 10⁻³ Pa to 1 Pa, and more preferably 10⁻² Pa to 1Pa. When it is lower than the above range, re-oxidization of thedielectric layer 2 becomes difficult, while when exceeding the aboveranges, the internal electrode layer 3 tends to oxidize. Other conditionof the thermal treatment is preferably as below.

holding time: 0 to 6 hours, particularly 2 to 5 hours

cooling rate: 50 to 500° C./hour, particularly 100 to 300° C./hour

atmosphere gas: wet N₂ gas, etc.

Note that to wet a N₂ gas or a mixed gas, etc., for example, a wetter,etc. may be used. In this case, the water temperature is preferably 0 to75° C. or so. Also, the binder removal processing, firing and thermaltreatment may be performed continuously or separately. When performingcontinuously, the atmosphere is changed without cooling after the binderremoval processing, continuously, the temperature is raised to theholding temperature at firing to perform firing. Next, it is cooled andthe thermal treatment is preferably performed by changing the atmospherewhen the temperature reaches to the holding temperature of the thermaltreatment. On the other hand, when performing them separately, afterraising the temperature to the holding temperature at the binder removalprocessing in an atmosphere of a N₂ gas or a wet N₂ gas, the atmosphereis changed, and the temperature is furthermore raised, when firing.After that, after cooling the temperature to the holding temperature atthe thermal treatment, it is preferable that the cooling continues bychanging the atmosphere again to a N₂ gas or a wet N₂ gas. Also, in thethermal treatment, after raising the temperature to the holdingtemperature under the N₂ gas atmosphere, the atmosphere may be changed,or the entire process of the thermal processing may be in a wet N₂ gasatmosphere.

The thus obtained sintered body (element body 4) is subjected to endsurface polishing, for example, by barrel polishing and sand-blast,etc., then, a terminal electrode slurry is burnt to form terminalelectrodes 6 and 8. For example, a firing condition of the terminalelectrode slurry is preferably in a mixed gas of wet N₂ and H₂ at 600 to800° C. for 10 minutes to 1 hour or so. In accordance with need,plating, etc. is performed on the terminal electrodes 6 and 8 to form apad layer. Note that the terminal electrode paste may be fabricated inthe same way as the electrode slurry explained above.

A multilayer ceramic capacitor of the present invention produced asabove is mounted on a print substrate, etc. by soldering, etc. and usedfor a variety of electronic equipments.

In a method of producing a multilayer ceramic capacitor using thedielectric slurry (green sheet slurry) and the green sheet 10 aaccording to the present embodiment, a polyvinyl acetal resin having apolymerization degree in a specific range, a butyralation degree in aspecific range and a residual acetyl group amount of a predeterminedvalue or less is used as a binder. Therefore, even an extremely thingreen sheet 10 a of, for example, 5 μm or less is strong enough to bepeeled from the carrier film 30 and has preferable adhesiveness andhandlability. Also, surface roughness of the sheet 10 a is small andstackability is excellent. Therefore, it becomes easy to stack a largenumber of green sheets 10 a via electrode layers 12 a, and it is alsopossible to stack without the adhesive layers 28 in accordance withneed.

Also, in a production method of a multilayer ceramic capacitor using thedielectric slurry (green sheet slurry) and the green sheet 10 aaccording to the present embodiment, a specific kind of dispersanthaving a specific range of HLB is used. Therefore, even an extremelythin green sheet 10 a of, for example, 5 μm or thinner is strong enoughto be peeled from the carrier film 30 and has preferable adhesivenessand handlability. Also, surface roughness of the sheet 10 a is small andstackability is excellent. Therefore, it becomes easy to stack a largenumber of green sheets 10 a via electrode layers 12 a, and it is alsopossible to stack without the adhesive layers 28 in accordance withneed.

Furthermore, in a production method of a multilayer ceramic capacitorusing the dielectric slurry (green sheet slurry) and the green sheet 10a according to the present embodiment, an antistatic agent is containedin the dielectric slurry, and the antistatic agent is an imidazolinebased antistatic agent. Therefore, even in the case of an extremely thingreen sheet 10 a of, for example, 5 μm or thinner, it is possible toproduce a green sheet 10 a having sufficient strength to be peeled fromthe carrier film 30 as a support body, wherein static electricitygenerated at the time of being peeled from the carrier film 30 issuppressed, and the adhesiveness and handlability are preferable. Also,surface roughness of the sheet 10 a is small and stackability isexcellent. Therefore, it becomes easy to stack a large number of greensheets 10 a via electrode layers 12 a, and it is also possible to stackwithout the adhesive layers 28 in accordance with need.

Also, in a production method of a multilayer ceramic capacitor accordingto the present embodiment, a dry type electrode layer 12 a can be easilyand highly accurately transferred to the surface of the green sheet 10 awithout damaging or deforming the green sheet 10 a.

Furthermore, in the production method of the present embodiment, theadhesive layer 28 is formed on a surface of an electrode layer or agreen sheet by a transfer method, and the electrode layer 12 a isadhered to the surface of the green sheet 10 a via the adhesive layer28. By forming the adhesive layer 28, at the time of transferring theelectrode layer 12 a to the surface of the green sheet 10 a by adhering,a high pressure and heat become unnecessary and adhesion under a lowpressure and low temperature becomes possible. Accordingly, even whenthe green sheet 10 a is extremely thin, the green sheet 10 a is notdamaged, the electrode layer 12 a and the green sheet 10 a can bepreferably stacked, and a short-circuiting defect, etc. is not caused.

Also, for example, by making an adhesive force of the adhesive layer 28stronger than adherence force of the release layer 22 and also makingthe adherence force of the release layer 22 stronger than an adhesiveforce between the green sheet 10 a and the carrier film 30, the carrierfilm 30 on the green sheet 10 a side can be selectively and easilyremoved.

Furthermore, in the present embodiment, since the adhesive layer 28 isnot directly formed on the surface of the electrode layer 12 a or greensheet 10 a by an applying method, etc. but formed by a transfer method,components of the adhesive layer 28 do not soak in the electrode layer12 a or green sheet 10 a and an extremely thin adhesive layer 28 can beformed. For example, a thickness of the adhesive layer 28 can be made asthin as 0.02 to 0.3 μm or so. Even if the thickness of the adhesivelayer 28 is thin, components of the adhesive layer 28 do not soak in theelectrode layer 12 a or green sheet 10 a, so that the adhesive force issufficient. Moreover, an adverse effect is not given to a composition ofthe electrode layer 12 a or green sheet 10 a.

Note that the present invention is not limited to the above embodimentsand may be variously modified within the scope of the present invention.

For example, a method of the present invention is not limited to theproduction method of multilayer ceramic capacitors and may be applied asa production method of other multilayer type electronic devices.

EXAMPLES

Below, the present invention will be explained based on further detailedexamples, but the present invention is not limited to the examples.

Example 1 Production of Green Sheet Slurry

As a starting material of ceramic powder, BaTiO₃ powder (BT-035 andBT-02 made by Sakai Chemical Industry Co., Ltd.) was used. A ceramicpowder subcomponent additives were prepared to satisfy(Ba_(0.6)Ca_(0.4))SiO₃: 1.48 parts by weight, Y₂O₃: 1.01 parts byweight, MgCO₃: 0.72 wt %, Cr₂O₃: 0.13 wt % and V₂O₅: 0.045 wt % withrespect to 100 parts by weight of the BaTiO₃ powder.

First, only the subcomponents were mixed by a ball-mill to obtainslurry. Namely, the subcomponent additives (total amount 8.8 g) and asolvent (16 g), wherein ethanol/n-propanol is 1:1, were preliminaryground by a ball-mill for 20 hours. Next, the preliminary ground slurryof the subcomponent additives, ethanol: 38 g, n-propanol: 38 g, xylene:28 g, mineral spirit: 14 g, DOP (dioctyl phthalate) as a plasticizercomponent: 6 g and a polyethylene glycol based nonionic dispersant(HLB=5 to 6) as a dispersant: 1.4 g were added to BaTiO₃: 191.2 g andmixed by a ball-mill for 4 hours. Note that a block polymer ofpolyethylene glycol and fatty ester was used as the polyethylene glycolbased nonionic dispersant (HLB=5 to 6) as a dispersant.

Next, as a binder resin, the dispersion slurry was added with 15%lacquer (BH6 made by Sekisui Chemical Co., Ltd. was dissolved inethanol/n-propanol=1:1) of BH6 (polybutyral resin: PVB) made by SekisuiChemical Co., Ltd. by 6 wt % as a solid content (80 g as a lacqueradding quantity). After that, by ball-milling for 16 fours, a ceramicslurry (green sheet slurry) was obtained.

A polymerization degree of a polybutyral resin as the binder resin was1400, a butyralation degree thereof was 69±3%, and a residual acetylgroup amount thereof was 3±2%. The binder resin was contained by 6 partsby weight in the ceramic slurry with respect to 100 parts by weight ofceramic powder (including ceramic powder subcomponent additives). Also,when assuming that total volume of the ceramic powder, binder resin andplasticizer in the ceramic slurry was 100 volume %, the volume ratioaccounted by the ceramics powder was 67.31 volume %.

Also, DOP as a plasticizer was contained in the ceramic slurry by 50parts by weight with respect to 100 parts by weight of the binder resin.Water was contained by 2 parts by weight with respect to 100 parts byweight of the ceramic powder. The polyethylene glycol based nonionicdispersant as a dispersant was contained by 0.7 part by weight withrespect to 100 parts by weight of the ceramic powder.

Also, in the slurry, mineral spirit of at least any one of a hydrocarbonbased solvent, industrial gasoline, kerosene and solvent naphtha wasadded by 5 parts by weight with respect to 100 parts by weight of theceramic powder. Furthermore, the slurry contains an alcohol basedsolvent and an aromatic solvent as a solvent. When assuming that totalweight of the alcohol based solvent and aromatic solvent was 100 partsby weight, toluene as an aromatic solvent was contained by 15 parts byweight.

Viscosity of the slurry was 180 mPa·S. The viscosity of the slurry wasmeasured by using a B-type viscosimeter and using S21 as a rotor, andmeasurement was made at a temperature of 25° immediately after theslurry was obtained. The rotation rate at the time of measurement was 50rpm.

Production of Green Sheet

The slurry obtained as above was applied to a PET film as a supportingfilm to be a thickness of 2 μm by a wire bar coater and dried to producea green sheet. The applying rate was 50 m/min. and the drying conditionwas a temperature in the drying furnace of 60° C. to 70° C. and dryingtime of 2 minutes.

Evaluation of Green Sheet

After that, evaluation was made on sheet density, surface roughness,sheet tensile strength, sheet ductility, adhesiveness (stackability,release strength) and a total evaluation of the green sheet. The resultsare shown in Table 1. TABLE 1 Table 1 (Selection of Resin) Resin AmountAdhe- Adding of Sheet Surface Tensile Sheet sive- Kind of Quantity Kindof Plasticize Water Dispersant Viscosity Density Roughness StrengthStress ness Evalu- Resin (PHP) Plasticizer (PHR) (PHP) (PHP) (mPa · s)(g/cm³) (μm) (MPa) (%) (N/cm²) ation Example 1 PVB 6 DOP 50 2 0.7 1803.4 0.55 8.2 49 14.5 ◯ Comparative PVAc 6 DOP 50 2 0.7 230 3.3 *0.62 6.6*23 *3.2 X Example 1 Comparative Acryl 6 DOP 50 0 0.7 200 3.4 0.51 *1.2156 *6.6 X Example 2 (MMA- BA)

Note that the sheet density was obtained by measuring a thickness of thesheet after drying, measuring weight of the sheet, and dividing theweight of the sheet by the volume. The surface roughness was measured bymeasuring average surface roughness Rz by using a surface roughnessmeasuring device made by Kosaka Laboratory Ltd. The sheet tensilestrength and the sheet ductility were obtained by using a tensile testmachine of Instron 5543, preparing 5 sheets cut to be a dumbbell shapeas samples, pulling the samples respectively at a tensile rate of 8mm/min., obtaining strength and stretch at the time of breaking andcalculating an average value.

The adhesiveness was evaluated as below. First, 10 samples obtained bycutting a dried sheet to 50 mm×15 mm were prepared, and 5 sets obtainedby adhering (tentative stack) two of the samples each were prepared.Each of the sheet sets were preheated at 70° C. for 5 minutes andadhered under a condition of 70° C. for one minute under about 2 MPa.After that, both surfaces of the sheets of each set were appliedtwo-sided tape, the sheets of each set were pulled in the direction ofdetaching by using the tensile test machine of Instron 5543, and releasestrength at the time of being detached was measured. The higher therelease strength, the more excellent it is in adhesiveness.

In the total evaluation, those having sheet density of 3.3 g/cm³ ormore, surface roughness of 0.6 μm or less, sheet tensile strength of 6.0MPa or more, sheet ductility of 37% or more, and release strength ofadhesiveness of 10 N/cm² or more were determined to be good (o), andthose not satisfying even one of the conditions were determined to bedefective (x). Note that “*” in front of a number in the table indicatesthat it exceeds a preferable range. It is the same also in Tables below.

Comparative Example 1

Other than using polyvinyl acetal resin (PVAc) of a production numberBX-1 made by Sekisui Chemical Co., Ltd. as a binder resin, a green sheetwas produced in the same way as in the example 1 and the evaluation wasmade in the same way. The results are shown in Table 1.

Comparative Example 2

Other than using an acrylic resin (MMA-BA) having a molecular weight of450,000 and a Tg of 70° C. as a binder resin, a green sheet was producedin the same way as in the example 1 and the evaluation was made in thesame way. The results are shown in Table 1.

Evaluation 1

As shown in Table 1, it was confirmed that a polyvinyl butyral resin(PVB) was preferable as a binder resin

Examples 2 to 3 and Comparative Examples 3 to 5

As shown in Table 2, other than using a polybutyral resin having adifferent production number (grade) made by Sekisui Chemical Co., Ltd.having a polymerization degree of 300 to 2400, a green sheet wasproduced in the same way as in the example 1 and the evaluation was madein the same way. The results are shown in Table 2. TABLE 2 Table 2(Polimerization Degree) Residual Butyralation Acetyl Resin Adding Amountof Polimerization Degree Group Quantity Plasticizer Water Grade Degreeof Resin (±3%) ±2% (PHP) Plasticizer (PHR) (PHP) Comparative BL-1H 30069 3 6 DOP 50 2 Example 3 Comparative BM-2 850 68 3 6 ↑ 50 ↑ Example 4Example 2 BH-S 1000 73 5 6 ↑ 50 ↑ Example 1 BH6 1400 69 3 6 ↑ 50 ↑Example 3 BH3 1700 65 3 6 ↑ 50 ↑ Comparative 2400 69 3 6 ↑ 50 ↑ Example5 Sheet Sheet Surface Tensile Sheet Dispersant Viscosity DensityRoughness Strength Stress Adhesiveness (PHP) (mPa · s) (g/cm³) (μm)(MPa) (%) (N/cm²) Evaluation Comparative 0.7 180 3.51 0.47 *2.7 122 16.6X Example 3 Comparative ↑ 170 3.43 0.52 *3.3 98 16 X Example 4 Example 2↑ 180 3.43 0.53 6.1 68 16.1 ◯ Example 1 ↑ 180 3.4 0.55 8.2 49 14.5 ◯Example 3 ↑ 230 3.3 0.59 8.5 43 13.1 ◯ Comparative ↑ 280 *3.14 *0.63 9.4*35 *8.8 X Example 5

Evaluation 2

As shown in Table 2, it was confirmed that a preferable polymerizationdegree of the polybutyral resin was 1000 or higher and 1700 or lower. Itwas confirmed that, when the polymerization degree was too low, thesheet tensile strength tended to decline, while when the polymerizationdegree was too high, it was liable that the sheet density declined,sheet surface roughness declined, and sheet ductility and adhesivenessalso declined.

Example 3 and Comparative Example 6

As shown in Table 3, other than using a polybutyral resin having adifferent production number (grade) made by Sekisui Chemical Co., Ltd.having a butyralation degree of 65 to 78, a green sheet was produced inthe same way as in the example 1 and the evaluation was made in the sameway. The results are shown in Table 3. TABLE 3 Table 3 (ButyralationDegree) Before Correction Residual Resin Adding Amount of PolimerizationButyralation Acetyl Amount Plasticizer Water Grade Degree of ResinDegree Group (PHP) Plasticizer (PHR) (PHP) Example 3 BH3 1700 65 3 6 DOP50 2 Example 1 BH6 1400 69 3 6 ↑ 50 ↑ Comparative 1400 78 3 6 ↑ 50 ↑Example 6 Sheet Surface Tensile Sheet Dispersant Viscosity DensityRoughness Strength Stress Adhesiveness (PHP) (mPa · s) (g/cm³) (μm)(MPa) (%) (N/cm²) Evaluation Example 3 0.7 230 3.3 0.59 8.5 43 13.1 ∘Example 1 ↑ 180 3.4 0.55 8.2 49 14.5 ∘ Comparative ↑ 350 * 3.1   *0.66   6.8 52 * 8.9  x Example 6

Evaluation 3

As shown in Table 3, it was confirmed that a preferable butyralationdegree of the polybutyral resin was 65% or higher and 78% or lower. Itwas confirmed that when the butyralation degree was too low, the sheetductility tended to decline, while when too high, sheet surfaceroughness tended to deteriorate.

Example 3 and Comparative Examples 7 and 8

As shown in Table 4, other than using a polybutyral resin having adifferent production number (grade) made by Sekisui Chemical Co., Ltd.having a residual acetyl group amount of 3 to 13, a green sheet wasproduced in the same way as in the example 1 and the evaluation was madein the same way. The results are shown in Table 4. TABLE 4 Table 4(Residual Acetyl Group) Residual Resin Adding Amount of PolimerizationButyralation Acetyl Amount Plasticizer Water Grade Degree of ResinDegree Group (PHP) Plasticizer (PHR) (PHP) Example 3 BH3 1700 65 3 6 DOP50 2 Comparative BHA 1700 62 6 6 ↑ 50 ↑ Example 7 Comparative BHA 170058 13 6 ↑ 50 ↑ Example 8 Sheet Surface Tensile Sheet DispersantViscosity Density Roughness Strength Stress Adhesiveness (PHP) (mPa · s)(g/cm³) (μm) (MPa) (%) (N/cm²) Evaluation Example 3 0.7 230 3.3 0.59 8.543 13.1 ◯ Comparative ↑ 200 *3.2 *0.62 8.3 47 12.2 X Example 7Comparative ↑ 150 *3.1 *0.66 *8 48 12.1 X Example 8

Evaluation 4

As shown in Table 4, it was confirmed that a preferable residual acetylgroup amount of the polybutyral resin was less than 6%. It was confirmedthat when the residual acetyl group amount was too large, it was liablethat the sheet density declined, surface roughness increased andadhesiveness declined.

Examples 4 to 7 and Reference Examples 1 to 7

As shown in Table 5, other than changing an adding weight ratio parthandread of pigment (PHP) of the polybutyral resin as a binder resin ina range of 2 to 7 parts by weight with respect to 100 parts by weight ofceramic powder, a green sheet was produced in the same way as in theexample 1 and the evaluation was made in the same way. The results areshown in Table 5. Note that the example 6 is the same as the example 1.TABLE 5 Table 5 (Binder Content) Resin Residual Adding Volume Amount ofPolimerization Butyralation Acetyl Amount Ratio Plasticizer Water Degreeof Resin Degree Group (PHP) Volume % Plasticizer (PHR) (PHP) Reference1400 69 3 2 86.06 DOP 50 3 Example 1 Reference ↑ ↑ ↑ 2.5 83.17 ↑ ↑ ↑Example 2 Reference ↑ ↑ ↑ 3 80.46 ↑ ↑ ↑ Example 3 Reference ↑ ↑ ↑ 3.577.92 ↑ ↑ ↑ Example 4 Reference ↑ ↑ ↑ 4 75.54 ↑ ↑ ↑ Example 5 Reference↑ ↑ ↑ 4.5 73.30 ↑ ↑ ↑ Example 6 Example 4 ↑ ↑ ↑ 5 71.18 ↑ ↑ ↑ Example 5↑ ↑ ↑ 5.5 69.19 ↑ ↑ ↑ Example 6 ↑ ↑ ↑ 6 67.31 ↑ ↑ ↑ Example 7 ↑ ↑ ↑ 6.565.52 ↑ ↑ ↑ Reference ↑ ↑ ↑ 7 63.83 ↑ ↑ ↑ Example 7 Sheet SurfaceTensile Sheet Dispersant Viscosity Density Roughness Strength StressAdhesiveness (PHP) (mPa · s) (g/cm³) (μm) (MPa) (%) (N/cm²) EvaluationReference 0.7 120 3.63 0.37 *1.8 *8.9 *0 X Example 1 Reference ↑ 1303.62 0.37 *2.3 *13 *0 X Example 2 Reference ↑ 150 3.61 0.38 *3 *16 *1.3X Example 3 Reference ↑ 150 3.59 0.39 *3.9 *21 *1.5 X Example 4Reference ↑ 160 3.57 0.4 *4.8 *26 *2.2 X Example 5 Reference ↑ 160 3.540.42 *5.7 *32 *6.9 X Example 6 Example 4 ↑ 170 3.51 0.43 6.4 37 10.1 ◯Example 5 ↑ 170 3.46 0.47 7.4 43 12.8 ◯ Example 6 ↑ 180 3.4 0.55 8.2 4914.5 ◯ Example 7 ↑ 190 3.33 0.6 9.7 56 16.8 ◯ Reference ↑ 210 *3.24*0.68 11.1 62 18.9 X Example 7

Evaluation 5

As shown in Table 5, it was confirmed that a preferable adding weightratio (PHP) of the polybutyral resin as a binder resin was 5 parts byweight or more and 6.5 parts by weight or less with respect to 100 partsby weight of ceramic powder. It was confirmed that when the weight ratiowas too low, the tensile strength, sheet ductility and adhesivenessdeclined, while when the weight ratio was too high, it was liable thatthe sheet density declined and the surface roughness increased.

Also, when assuming that total volume of the ceramic powder, binderresin and plasticizer was 100 volume %, it was confirmed that apreferable volume ratio accounted by the ceramic powder was 64.3% ormore and 72% or less. It was confirmed that when the volume ratio wastoo low, the sheet density declined and surface roughness increased,inversely, when the volume ratio was too high, it was liable that thetensile strength, sheet ductility and adhesiveness declined.

Examples 8 to 11 and Reference Examples 8 to 18

As shown in Table 6, other than changing an adding weight ratio (parthandread of resin (PHR)) of dioctyl phthalate (DOP) as a plasticizer ina range of 30 to 100 parts by weight with respect to 100 parts by weightof a binder resin, a green sheet was produced in the same way as in theexample 1 and the evaluation was made in the same way.

Also, as shown in Table 6, other than using dibutyl phthalate (DBP) orbenzylbutyl phthalate (BBP) as a plasticizer and changing an addingweight ratio (PHR) of the plasticizer in a range of 30 to 100 parts byweight with respect to 100 parts by weight of a binder resin, a greensheet was produced in the same way as in the example 1 and theevaluation was made in the same way. The results are shown in Table 6.Note that the example 9 is the same as the example 1. TABLE 6 Table 6(Kind and Amount of Plasticity) Residual Resin Adding Amount ofPolimerization Butyralation Acetyl Amount Plasticizer Water Grade Degreeof Resin Degree Group (PHP) Plasticizer (PHR) (PHP) Reference BH-6 140069 3 6 DOP 30 2 Example 8 Example 8 ↑ ↑ ↑ ↑ ↑ ↑ 40 ↑ Example 9 ↑ ↑ ↑ ↑ ↑↑ 50 ↑ Example 10 ↑ ↑ ↑ ↑ ↑ ↑ 60 ↑ Example 11 ↑ ↑ ↑ ↑ ↑ ↑ 70 ↑ Reference↑ ↑ ↑ ↑ ↑ ↑ 80 ↑ Example 9 Reference ↑ ↑ ↑ ↑ ↑ ↑ 100 ↑ Example 10Reference ↑ ↑ ↑ ↑ ↑ DBP 30 ↑ Example 11 Reference ↑ ↑ ↑ ↑ ↑ ↑ 50 ↑Example 12 Reference ↑ ↑ ↑ ↑ ↑ ↑ 70 ↑ Example 13 Reference ↑ ↑ ↑ ↑ ↑ ↑100 ↑ Example 14 Reference ↑ ↑ ↑ ↑ ↑ BBP 30 ↑ Example 15 Reference ↑ ↑ ↑↑ ↑ ↑ 50 ↑ Example 16 Reference ↑ ↑ ↑ ↑ ↑ ↑ 70 ↑ Example 17 Reference ↑↑ ↑ ↑ ↑ ↑ 100 ↑ Example 18 Sheet Surface Tensile Sheet DispersantViscosity Density Roughness Strength Stress Adhesiveness (PHP) (mPa · s)(g/cm³) (μm) (MPa) (%) (N/cm²) Evaluation Reference 0.7 180 3.45 0.538.2 *33 *7.2 X Example 8 Example 8 ↑ 180 3.4 0.53 8.4 41 10.2 ◯ Example9 ↑ 180 3.4 0.55 8.2 49 14.5 ◯ Example 10 ↑ 180 3.34 0.56 7.1 61 16.3 ◯Example 11 ↑ 180 3.3 0.59 6.6 70 18 ◯ Reference ↑ 170 *3.25 *0.62 *5.682 19.4 X Example 9 Reference ↑ 170 *3.2 *0.64 *4.2 104 20.2 X Example10 Reference ↑ 180 3.43 0.53 6.3 52 *0 X Example 11 Reference ↑ 180 3.370.56 *4.4 80 *0 X Example 12 Reference ↑ 180 3.32 *0.62 *2.8 94 *3.3 XExample 13 Reference ↑ 170 *3.24 *0.67 *2.3 155 *4.3 X Example 14Reference ↑ 180 3.44 0.54 7.2 51 *0 X Example 15 Reference ↑ 180 3.390.54 6.1 87 *4.5 X Example 16 Reference ↑ 180 3.31 0.6 *2.9 105 *6.2 XExample 17 Reference ↑ 170 *3.28 *0.64 *2.5 164 *6.6 X Example 18

Evaluation 6

As shown in Table 6, it was confirmed that DOP was preferable as aplasticizer and the adding weight ratio was preferably 40 parts byweight or more and 70 parts by weight or less. When the weight ratio wastoo low, the sheet ductility and adhesiveness declined and when theweight ratio was too high, it was liable that the sheet densitydeclined, surface roughness increased, and tensile strength declined.

Examples 12 to 15 and Reference Examples 19 to 22

As shown in Table 7, other than changing an adding weight ratio (PHP) ofwater in a range of 0.1 to 10 parts by weight with respect to 100 partsby weight of ceramic powder, a green sheet was produced in the same wayas in the example 1 and the evaluation was made in the same way exceptthat a filtration test was added. The results are shown in Table 7. Notethat the example 13 is the same as the example 1. TABLE 7 Table 7 (WaterContent) Resin Residual Adding Amount of Polimerization ButyralationAcetyl Amount Plasticizer Water Dispersant Grade Degree of Resin DegreeGroup (PHP) Plasticizer (PHR) (PHP (PHP) Reference BH6 1400 69 3 6 DOP50 0.1 0.7 Example Reference ↑ ↑ ↑ ↑ 6 ↑ ↑ 0.5 ↑ Example Example 12 ↑ ↑↑ ↑ 6 ↑ ↑ 1 ↑ Example 13 ↑ ↑ ↑ ↑ 6 ↑ ↑ 2 ↑ Example 14 ↑ ↑ ↑ ↑ 6 ↑ ↑ 4 ↑Example 15 ↑ ↑ ↑ ↑ 6 ↑ ↑ 6 ↑ Reference ↑ ↑ ↑ ↑ 6 ↑ ↑ 8 ↑ ExampleReference ↑ ↑ ↑ ↑ 6 ↑ ↑ 10 ↑ Example Sheet Surface Tensile SheetFiltration Viscosity Density Roughness Strength Stress Adhesiveness Test(mPa · s) (g/cm³) (μm) (MPa) (%) (N/cm²) (min.sec.) Evaluation Reference200 3.35 0.57 8 47 14.2 *— X Example Reference 190 3.37 0.57 8.4 48 14.4*6.46 X Example Example 12 190 3.41 0.53 8.3 49 14.7 2.50 ◯ Example 13180 3.4 0.55 8.2 49 14.5 2.25 ◯ Example 14 180 3.39 0.57 8.2 49 14.41.56 ◯ Example 15 200 3.3 0.59 8.1 50 14.6 3.44 ◯ Reference 230 *3.16*0.68 8 51 14.7 5.48 X Example Reference 230 *2.93 *0.76 7.4 55 15.2 — XExample

Evaluation of a filtration test was made by using as a filter paper aproduction No. 5C made by Advantech Co., Ltd., wherein a retainedparticle diameter was 1 μm, and measuring time that 200 g of a greensheet slurry passed through a filter paper area of 28.26 cm². Theshorter the passing time is, the more excellent it is in filtrationproperties. Being excellent in a filtration properties means thatflocculant products is a little in the slurry and the binder resin ispreferably dissolved. Those with filtration time of 3.50 (min. sec.) orshorter were determined to be good (o) in the total evaluation.

Evaluation 7

As shown in Table 7, it was confirmed that a preferable adding weightratio of water was 1 part by weight or more and 6 parts by weight orless. When the weight ratio was too low, the filtration propertiestended to become deteriorated, while when the weight ratio was too high,it was liable that the sheet density declined and surface roughnessincreased.

Examples 16 to 22 and Reference Examples 23 to 27

As shown in Table 8, other than changing an adding weight ratio (PHP) ofmineral spirit in a range of 1 to 20 parts by weight with respect to 100parts by weight of ceramic powder, a green sheet was produced in thesame way as in the example 1 and the evaluation was made in the sameway.

Also, other than changing a kind of a solvent as shown in Table 8instead of mineral spirit, or not containing this kind of solvent, agreen sheet was produced in the same way as in the example 1 and theevaluation was made in the same way. The results are shown in Table 8.Note that the example 20 is the same as the example 1. Also, that MIBKin Table 8 is methyl isobutyl ketone. TABLE 8 Table 8 (Kind of Solvent)Solvent Adding Sheet Surface Tensile Sheet Amount Viscosity DensityRoughness Strength Stress Adhesiveness Kind of Solvent (PHP) (mPa · s)(g/cm³) (μm) (MPa) (%) (N/cm²) Evaluation Example 16 n-dodecane 5 1803.33 0.57 7.2 43 11 ◯ Example 17 n-octane 5 180 3.42 0.57 7.9 45 15.2 ◯Example 18 kerosine 5 180 3.38 0.58 7.5 56 12.2 ◯ Reference mineralspirit 1 190 3.5 *0.63 8.1 40 *9.4 X Example 23 Example 19 mineralspirit 3 190 3.45 0.57 8.3 42 12.4 ◯ Example 20 mineral spirit 5 180 3.40.55 8.2 49 14.5 ◯ Example 21 mineral spirit 10 180 3.32 0.54 7.7 5117.3 ◯ Example 22 mineral spirit 15 170 3.3 0.55 7.4 55 20.3 ◯ Referencemineral spirit 20 180 *3.21 *0.61 6.5 47 22.3 X Example 24 ReferenceMIBK 5 180 3.42 *0.63 8.7 *31 10.5 X Example 25 Reference benzyl zcetate5 180 3.44 *0.64 8.9 *29 11.2 X Example 26 Reference none — 190 3.42*0.65 8.2 38 *8.5 X Example 27

Evaluation 8

As shown in Table 8, it was confirmed that it was preferable that atleast any one of a hydrocarbon based solvent, industrial gasoline,kerosene and solvent naphtha was added by 3 parts by weight or more and15 parts by weight or less. It was confirmed that when the weight ratiowas too low, it was liable that the surface roughness increased andadhesiveness declined, while when the weight ratio was too high, it wasliable that the sheet density declined and surface roughness increased.

Examples 23 to 25 and Reference Examples 28 to 31

As shown in Table 9, other than changing an adding weight ratio of anaromatic solvent (toluene) in a range of 5 to 50 parts by weight byassuming that total weight of an alcohol based solvent (ethanol andpropanol) and the aromatic solvent (toluene) was 100 parts by weight, agreen sheet was produced in the same way as in the example 1 andevaluation was made in the same way as in the examples 12 to 15. Theresults are shown in Table 9. Note that the example 24 is same as theexample 1. TABLE 9 Table 9 (Aromatic Solvent) Kind of Solvent SheetSurface Tensile Sheet Filtration ethanol propanol toluene ViscosityDensity Roughness Strength Stress Adhesiveness Rate (wt %) (wt %) (wt %)(mPa · s) (g/cm³) (μm) (MPa) (%) (N/cm²) (min. sec.) EvaluationReference 47.5 47.5 5 200 3.36 *0.67 8.5 38 *8.4 1.32 X Example 28Example 23 45 45 10 190 3.4 0.57 8.3 44 10.8 1.50 ◯ Example 24 42.5 42.515 180 3.4 0.55 8.2 49 14.5 2.25 ◯ Example 25 40 40 20 180 3.32 0.52 7.351 18.4 3.12 ◯ Reference 35 35 30 170 *3.28 0.58 6.1 58 20.3 *6.24 XExample 29 Reference 30 30 40 160 *3.19 *0.61 *5.5 45 23.4 *— X Example30 Reference 25 25 50 180 *3.05 *0.7 *4.3 40 27.3 *— X Example 31

Evaluation 9

As shown in Table 9, it was confirmed that a solvent in a slurrypreferably contains an alcohol based solvent and an aromatic solvent,and the aromatic solvent is preferably contained by 10 parts by weightor more and 20 parts by weight or less when assuming that a total weightof the alcohol based solvent and aromatic solvent was 100 parts byweight. It was confirmed that when the weight ratio was too low, it wasliable that the surface roughness increased and adhesiveness declined,while when the weight ratio was too high, the filtration propertiesbecame deteriorated, sheet density declined, surface roughness increasedand tensile strength declined.

Reference Example 32

As shown in Table 10, other than not to obtain a solution by dissolvingBH6 (polybutyral resin: PVB) made by Sekisui Chemical Co., Ltd. as abinder resin in an alcohol based solvent, whereinethanol/n-propanol=1:1, and filtrating in advance, and binder resinpowder was directly added into a slurry, a green sheet was produced inthe same way as in the example 1, and evaluation was made in the sameway as in the examples 12 to 15. The results are shown in Table 10.TABLE 10 Table 10 (Binder Adding Method) Surface Filtration BinderAdding Viscosity Sheet Density Roughness Tensile Strength Sheet StressAdhesiveness Rate Method (mPa · s) (g/cm³) (μm) (MPa) (%) (N/cm²) (min.sec.) Evaluation Example 1 added by solution 180 3.4 0.55 8.2 49 14.52.25 ◯ Reference added by powder 210 *3.13 *0.68 7.8 47 13.8 *— XExample 32

Evaluation 10

As shown in Table 10, it was confirmed that it was preferable that abinder resin was dissolved in an alcohol based solvent of at least onekind of methanol, ethanol, propanol and butanol and filtered to make asolution in advance, and the above ceramic powder and other componentsare added to the solution. Otherwise, it was liable that the filtrationproperties became deteriorated and surface roughness increased.

Examples 1a to 1 g

As a dispersant, as shown in Table 11, other than using

a nonionic dispersant of sorbitan monostearate (HLB=4 or more and lessthan 5),

a polyethylene glycol based nonionic dispersant (HLB=5 to 6),

a nonionic dispersant of polyethylene glycol based polyoxylene stearinether (HLB=larger than 6 and not more than 7),

a polycarboxylate ammonium based dispersant,

a maleic acid based dispersant,

a sodium dialkylsulfosuccinate as a succinate based dispersant, and

polyoxyethylene lauryl aminoether (HLB=9.8) as an amine baseddispersant, a green sheet was produced in the same way as in the example1 and the same evaluation was made. The results are shown in Table 11.

Note that evaluation of the filtration test was made by using as afilter paper a production No. 5C made by Advantech Co., Ltd., wherein aretained particle diameter was 1 μm, and measuring time that 200 g of agreen sheet slurry passed through a filter paper area of 28.26 cm² underpressure of 0.2 MPa. The shorter the passing time is, the more excellentit is in filtration properties. Being excellent in filtration propertiesmeans that flocculant products are a little in the slurry and the binderresin is preferably dissolved. Those unable to be measured due toclogging in the measurement of the filtration rate were indicated by “-”in Table 11. It is the same also in Table 12. TABLE 11 Table 11 (Kind ofDispersant) Adhe- Sheet Surface Tensile Sheet sive- FiltrationDispersant Viscosity Density Roughness Strength Stress ness Rate Kind ofDispersant (PHP) (mPa · s) (g/cm³) (μm) (MPa) (%) (N/cm²) (min. sec.)Evaluation Example 1a sorbitan monostearate HLB = 4 to 5 0.7 250 *3.22*0.64 7.7 45 16.6 — X Example 1b polyethylene glycol based HLB = 5 to 60.7 180 3.4 0.55 8.2 49 14.5 2.25 ◯ Example 1c polyethylene glycol basedHLB = 6 to 7 0.7 220 *3.25 *0.66 6.7 42 15.3 — X Example 1dpolycarboxylate based 0.7 240 3.43 0.5 6.6 *31 14.3 3.44 X Example 1emaleic acid based 0.7 250 3.41 0.51 6.5 *32 16.5 — X Example 1fsuccinate based 0.7 250 *3.29 *0.63 7.5 42 16 — X Example 1g amine based0.7 320 *3.12 *0.66 6.4 *36 15.5 — X

Evaluation 11

As shown in Table 11, it was confirmed that a polyethylene glycol basednonionic dispersant (HLB=5 to 6) was the most preferable as adispersant.

Note that in the total evaluation in the Table 11, those having sheetdensity of 3.3 g/cm³ or more, surface roughness of 0.6 μm or less, sheettensile strength of 6.0 MPa or more, sheet ductility of 37% or more,release strength of adhesiveness of 8.9 N/cm² or more, and filtrationrate (filtration time) of 4.50 (min. sec.) or shorter were determined tobe good (o), and those not satisfying even one of the conditions weredetermined to be defective (x). The determination is the same also inTable 12.

Examples 1h to 1m

Other than changing a content of a dispersant in a range of 0.2 to 2parts by weight with respect to 100 parts by weight of ceramic powder, agreen sheet was produced in the same way as in the example 1b andevaluation was made in the same way. The results are shown in Table 12.TABLE 12 Table 12 (Amount of Dispersant) Sheet Surface Tensile SheetFiltration Dispersant Viscosity Density Roughness Strength StressAdhesiveness Rate Kind of Dispersant (PHP) (mPa · s) (g/cm³) (μm) (MPa)(%) (N/cm²) (min. sec.) Evaluation Example 1h polyethylene glycol 0.2280 *3.29 *0.61 8.2 59 14.4 — X based HLB = 5 to 6 Example 1i ↑ 0.5 2203.35 0.58 8.3 53 14.2 4.12 ◯ Example 1j ↑ 0.7 180 3.4 0.55 8.2 49 14.52.25 ◯ Example 1k ↑ 1 130 3.58 0.49 7.6 45 10.3 1.4 ◯ Example 1l ↑ 1.5100 3.63 0.46 6.9 41 8.9 1.32 ◯ Example 1n ↑ 2 90 3.53 0.51 *5.3 37 *6.62.21 X

Evaluation 12

As shown in Table 12, it was confirmed that a content of a dispersantwas preferably in a range of 0.5 to 1.5 parts by weight, and morepreferably in a range of 0.5 to 1.0 part by weight with respect to 100parts by weight of ceramic powder.

Examples 1n to 1y

As shown in Table 13, other than adding a variety of antistatic agentsin a green sheet slurry by variable parts by weight (PHP) with respectto 100 parts by weight of ceramic powder, a green sheet was produced inthe same way as in the example 1 and evaluation was made in the sameway. The results are shown in Table 13.

Note that static electricity (electrification property) was evaluated asbelow. Namely, measurement was made by using S55-1 made by SHINKOcorporation at a distance from the green sheet 1 cm immediately afterremoving the green sheet. The measurement value is a value measuredafter 5 seconds from removal. The less the static electricity (kV) to begenerated is, the more preferable. When static electricity generates,the sheet gets wrinkled, so that stacking with high accuracy becomesdifficult. TABLE 13 Table 13 (Antistatic Agent) Adding Sheet SurfaceTensile Sheet Adhesive- Static Amount Viscosity Density RoughnessStrength Stress ness electricity Kind of Antistatic Agent (PHP) (mPa ·s) (g/cm³) (μm) (MPa) (%) (N/cm²) (kV) Evaluation Example 1n amine based0.5 180 3.38 0.57 *5.8 41 17 27 X Example 1o imidazoline based 0.05 1803.4 0.53 8.2 49 14 *55 Δ Example 1p ↑ 0.1 180 3.41 0.53 8.2 49 14 36 ◯Example 1q ↑ 0.25 180 3.4 0.54 8.1 47 15 29 ◯ Example 1r ↑ 0.5 180 3.40.54 8.2 49 14 22 ◯ Example 1s ↑ 0.75 180 3.35 0.57 7.5 42 15 16 ◯Example 1t ↑ 1 180 *3.26 *0.61 6.0 *34 15 5.6 X Example 1u polyethylene0.5 180 3.41 0.55 7.8 *38 15 36 X glycol based Example 1v PEG400 0.5 1803.39 0.58 6.3 *36 16 *46 X Example 1w 2-3 butanediol 0.5 180 3.4 0.568.9 *22 *4 *71 X Example 1x glycerin 0.5 180 3.38 0.59 *4.3 *18 10 *70 XExample 1y none — 180 3.4 0.55 8.2 49 14 *72 Δ

In Table 13, octadecyl amine acetate was used as an amine basedsurfactant, 1-hydroxyethyl 2-alkylimidazoline quarternary salt was usedas an imidazoline based surfactant, polyethylene glycol dodecyl etherwas used as a polyethylene glycol based antistatic agent, and a productmade by NOF Corporation was used as PEG400.

Evaluation 13

As shown in Table 13, it was confirmed that an imidazoline basedsurfactant was preferable as an antistatic agent. Moreover, as shown inTable 13, it was confirmed that when an adding quantity of theantistatic agent was too small, the antistatic effect became small,while when too large, the surface roughness of the sheet becamedeteriorated and sheet strength declined.

Note that in the total evaluation shown in Table 13, those having sheetdensity of 3.3 g/cm³ or more, surface roughness of 0.6 μm or less, sheettensile strength of 6.0 MPa or more, sheet ductility of 40% or more,release strength of adhesiveness of 9 N/cm² or more, and staticelectricity of 36 or less were determined to be good (o), those notsatisfying even one of the conditions were determined to be defective(x), and those not satisfying the above standard only in theelectrostatic evaluation item were determined to be (Δ).

As explained above, according to the present invention, it is possibleto provide a green sheet slurry, a green sheet, a production method of agreen sheet slurry and a production method of a green sheet capable ofproducing a green sheet having enough strength to be removed from asupporting body, preferable adhesiveness and handlability even if thegreen sheet is extremely thin. Therefore, it is possible to provide aproduction method of an electronic device suitable to be made thinnerand multilayer.

1. A green sheet slurry, including ceramic powder, a binder resin, aplasticizer and a solvent, wherein said binder resin contains apolyvinyl butyral resin, a polymerization degree of the polybutyralresin is 1000 or more and 1700 or less, a nominal value of abutyralation degree of the resin is 65% or higher and 78% or lower, anda residual acetyl group amount is smaller than 6%.
 2. The green sheetslurry as set forth in claim 1, wherein said binder resin is containedby 5 parts by weight or more and 6.5 parts by weight or less withrespect to 100 parts by weight of said ceramic powder.
 3. The greensheet slurry as set forth in claim 1, containing diotycle phthalate assaid plasticizer by 40 parts by weight or more and 70 parts by weight orless with respect to 100 parts by weight of said binder resin.
 4. Thegreen sheet slurry as set forth in claim 1, characterized in that, whenassuming that total volume of said ceramic powder, binder resin andplasticizer is 100 volume %, a volume ratio accounted by said ceramicpowder is 64.3% or higher and 72% or lower.
 5. A green sheet slurry,including ceramic powder, a binder resin, a plasticizer and an organicsolvent, wherein water is contained by 1 part by weight or more and 6parts by weight or less with respect to 100 parts by weight of saidceramic powder.
 6. A green sheet slurry, characterized by includingceramic powder, a binder resin, a plasticizer, a solvent, and adispersant, wherein: said dispersant contains polyethylene glycol basednonionic dispersant, and a hydrophile-lipophile balance vale is 5 to 6;and said dispersant is added by 0.5 part by weight or more and 1.5 partsby weight or less with respect to 100 parts by weight of ceramic powder.7. A green sheet slurry, including ceramic powder, a binder resin, aplasticizer, a solvent, and an antistatic agent, wherein said antistaticagent contains an imidazoline based antistatic agent, and saidantistatic agent is contained by 0.1 part by weight or more and 0.75part by weight or less with respect to 100 parts by weight of saidceramic powder.
 8. A green sheet slurry, including ceramic powder, abinder resin, and a solvent, wherein said solvent contains an alcoholbased solvent and an aromatic solvent, and the aromatic solvent iscontained by 10 parts by weight or more and 20 parts by weight or lesswhen assuming that total weight of the alcohol based solvent andaromatic solvent is 100 parts by weight.
 9. A production method of agreen sheet slurry, for producing a green sheet slurry as set forth inclaim 1, characterized in that said binder resin is dissolved in analcohol based solvent of at least one kind of methanol, ethanol,propanol and butanol and filtered to make a solution in advance, andsaid ceramic powder and other components are added to the solution. 10.A production method of a ceramic green sheet, including the steps of:preparing a green sheet slurry as set forth in claim 1; and forming aceramic green sheet by using said green sheet slurry.
 11. A productionmethod of a ceramic electronic device, including the step of: preparinga green sheet slurry as set forth in claim 1; forming a ceramic greensheet by using said green sheet slurry; drying said green sheet;stacking dried green sheets via internal electrode layers to obtain agreen chip; and firing said green chip.
 12. A green sheet produced byusing a green sheet slurry as set forth in claim 1.